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A168132 Numbers m = sum_(k=1...n) sigma(k) / k such that sum_(k=1...n) sigma(k) / k is integer for any k. 2
1, 2, 7, 9, 14, 52, 149, 213, 673, 1778, 3653, 6831, 9868, 570972, 2835107, 3613594, 47211979, 60418265, 99909506, 1701207282, 4587170542, 10955668024, 29031152874, 114018751785, 813149731047 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Numbers m = A024916(k) / k such that A024916(k) / k is integer for any k. If a(14) exist must be bigger than 82000.

Corresponding values of k, and sum_(k=1...n) sigma(k) are given in A056550 and A168133. [From Jaroslav Krizek, Nov 21 2009]

LINKS

Table of n, a(n) for n=1..25.

EXAMPLE

Number a(3) = 7 is in sequence because A024916(8) / 8 = 56 / 8 = 7 is integer for k = 8.

CROSSREFS

Sequence in context: A190565 A102994 A226824 * A211280 A294863 A085544

Adjacent sequences:  A168129 A168130 A168131 * A168133 A168134 A168135

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Nov 18 2009, Dec 04 2009

EXTENSIONS

a(14)-a(25) from Donovan Johnson, Jun 16 2011

STATUS

approved

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Last modified October 22 07:29 EDT 2019. Contains 328315 sequences. (Running on oeis4.)